Device for pressurizing limbs

ABSTRACT

A device for applying pressure to a body limb comprises a sleeve containing individually inflatable cells, each cell being subdivided into longitudinally extending confluent compartments that are inflated and deflated essentially simultaneously. A messaging sleeve, an inflation unit for intermittent inflation of selected cells of the sleeve, and a detecting unit for detecting a temporo-spatial regime of cell inflation are provided. Applications include immobilization of fractured bones, and messaging of limbs to promote blood flow.

FIELD OF THE INVENTION

The present invention relates to medical devices and more specificallyto devices for immobilizing or massaging body limbs, for example, incases of edema, vein disorders such as chronic venous insufficiency(c.v.i.), varicose veins (v.v), varicose ulcers (v.u.) and others;prevention of deep vein thrombosis; and bone fractures.

GLOSSARY

In the following description and claims the terms “sleeve” and “cell”mean:

Sleeve—a hollow cylinder formed of a flexible material into the lumen ofwhich a body limb, e.g. an arm, leg or foot, may be inserted.

Cell—A section of a massaging sleeve which may be inflated or deflatedindependently of the remainder of the sleeve.

BACKGROUND OF THE INVENTION

In the condition known as edema, interstitial fluid is inadequatelydrained by the lymphatics. This causes an accumulation of fluid in theaffected tissues leading to painful swelling. When this occurs in a bodylimb, beneficial results are obtained by massaging the limb in such away as to force the fluid towards the proximal end of the limb and intothe trunk of the body. A number of apparatuses have been devised forthis purpose, for example, as disclosed in U.S. Pat. Nos. 5,117,812,5,007,411, 5,025,781 and 5,591,200. In these apparatuses the limb to betreated is inserted into a massaging sleeve having a plurality ofessentially circumferential cells along its length. Each cell is capableof being individually inflated by forcing a fluid into the interior ofthe cell in order to apply pressure to the limb segment contained withinthe cell. Each cell is made to undergo cycles of inflation and deflationin order to apply intermittent pressure on the limb segment which itencloses thus achieving a massaging effect on the limb. Theinflation-deflation cycles of the different cells in the sleeve aretypically staggered so as to generate peristaltic contractions of thesleeve, thus moving fluids inside the limb towards the trunk. Inaddition to being of benefit in cases of edema, these devices are alsouseful in the treatment of c.v.i., v.v., v.u. and the prevention of deepvein thrombosis.

In prior art devices, each cell in the sleeve, when deflated, formsessentially a circumferential band around the limb, the circumference ofwhich is selected to correspond to the circumference of the limb segmentcontained within the cell. Upon inflation, the cell assumes essentiallya toroidal shape. In this case, a decrease in the inner circumference ofa cell upon inflation is accompanied by an essentially identicalincrease in the outer circumference of the cell. For example, in orderto obtain a 36% decrease in the inner circumference of a cell uponinflation, the outer circumference of the inflated cell must be 36%larger than the original circumference of the limb segment containedtherein. The fractional decrease in the inner circumference of the cellcorresponds to the amount of pressure applied by the inflated cell tothe limb segment contained therein. Thus, in order to obtain usefullevels of pressure using prior art devices, the sleeve is of necessityvery bulky, stiff and uncomfortable in use and relatively large andpowerful compression pumps are required. Prior art devices thereforerequire the individual to be immobilized during treatment for prolongedperiods of time.

It is therefore the object of the present invention to provide a limbmassaging device in which the aforementioned disadvantages of the priorart devices are substantially reduced or eliminated.

SUMMARY OF THE INVENTION

In accordance with a first aspect of the present invention there isprovided a device for applying pressure to a body limb, comprising asleeve containing a plurality of individually inflatable cells, eachcell being subdivided into two or more longitudinally extendingconfluent compartments which are inflated and deflated essentiallysimultaneously.

The device according to the invention may, for example, be used toimmobilize a fractured bone in a limb by inserting the limb into thesleeve and inflating all the cells thereof so as to render the sleeverigid and inflexible for the duration of the treatment.

By one mode the invention provides a device for applying pressure to oneor more limbs of the body comprising:

(a) a massaging sleeve containing a plurality of individually inflatablecells, each cell being subdivided into two or more longitudinallyextending confluent compartments which are inflated and deflatedessentially simultaneously;

(b) means for the separate and intermittent inflation of any one of saidplurality of inflatable cells; and

(c) control means for determining the temporo-spatial regime of cellinflation.

Typically, and by way of a non-limiting example, a temporo-spatialregime of cell inflation is selected which generates peristalticcontractions of the sleeve. For example, with a sleeve containing 5cells numbered consecutively from the distal to the proximal end of thelimb, cell 1 would first be inflated, followed by cell 2. Cell 1 wouldthen be deflated and cell 3 inflated. Next, cell 2 is deflated as cell 4is inflated, and then cell 3 is deflated and cell 5 inflated. Finally,cell 4 and then cell 5 are deflated and the cycle begins again. Othertemporo-spatial regimes of cell inflation are also contemplated withinthe scope of the invention.

In accordance with a third aspect of the present invention there isprovided a method of massaging a limb of the body of an individualcomprising: inserting the limb to be treated into a massaging sleeve ofthe kind specified and inflating the cells of the sleeve according to apredetermined temporo-spatial regime.

The device according to the invention is applied for example, in casesof edema, c.v.i., v.v., v.u. or preventing deep vein thrombosis.

As will become evident through the description below, subdividing thecells of the sleeve into compartments according to the present inventionyields several advantages over prior art devices. Since the diameter ofthe inflated sleeve is not substantially larger than the diameter of thetreated limb, the sleeve may be worn under clothing and is thusconcealed during use. Moreover, the sleeve remains flexible andcomfortable during use so that the individual need not be immobilizedduring treatment. Furthermore, the volume of the inflated cells in thepresent invention is substantially less than in prior art devices, sothat a much smaller compressor need be used for inflating the cells.This in turn allows the controlling unit to be substantially lighterthan is required for prior art devices. These features allow theindividual to be completely ambulatory during treatment.

While in the description given below, the cells in the sleeve arealigned to form an elastic cylinder, the invention is not bound by thisconstraint and other types of sleeves are contemplated within the scopeof the invention. For example, the sleeve may initially be a pad whichis wrapped around the limb into an essentially cylindrical shape andthen fastened in this configuration by various means.

In operation, a cell is inflated by forcing a fluid into the interior ofthe cell between the inner and outer shells. While in the descriptiongiven below a deflated cell forms an essentially circumferential bandaround the limb, and the fluid used to inflate the cell is air, theinvention is not bound by these constraints, and other cell shapes andfluids are contemplated within the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be demonstrated by way of a non-limiting example,with reference to the accompanying drawings in which:

FIG. 1 shows a massage sleeve according to the invention in use on theleg of an individual;

FIG. 2 shows a massage sleeve according to the invention mounted on theleg of an individual drawn to a larger scale;

FIG. 3 shows a fractional perspective view of a massage sleeve accordingto the invention fitted with a control unit; and

FIGS. 4a and 4 b show a cross-section of a cell in the deflated andinflated states, respectively.

DESCRIPTION OF A SPECIFIC EMBODIMENT

In the following, an embodiment of the invention will be described foruse on the leg of an individual. However, it is to be understood thatthe invention is also intended for use on any body limb such as an arm,a foot, a part of a leg, arm or foot, and may be used on two or morelimbs simultaneously.

In FIG. 1, a patient is depicted wearing a massaging sleeve 1 of theinvention on her leg while carrying out her routine duties. In FIG. 1,the trouser leg of the patient is cut away to reveal the sleeve. Inpractice, however, the sleeve remains concealed from view, and due tothe facets of the present invention remains unnoticed even duringoperation when the cells are intermittently inflated. The sleeve 1 hasan inner and outer surface composed of a durable flexible material andis divided into a plurality of cells 2 along its length and each cell isconnected to the control unit 3 by a separate tube collectively labeled4 in FIG. 1. Sections of the sleeve may be of non-inflatable elasticmaterials 5, for example around the knee and ankle 5.

As can be seen in FIGS. 2 and 3, each cell has a fluid inlet opening 6to which a hose 4 from the control unit 3 is attached. The control unit3 contains a compressor capable of compressing and pumping ambient airinto one or more selected cells in the sleeve via the hoses 4. Thecontrol unit 3 allows a temporo-spatial regime of inflation anddeflation of the cells to be selected, e.g. a regime which generatesperistaltic contractions of the sleeve so as to force fluids inside thelimb towards the proximal end of the limb, or a regime which enhancesthe flow of the venous blood in the limb. The continuity of theperistalsis is enhanced by interdigitating the compartments of adjacentcells in the massaging sleeve as shown in FIGS. 2 and 3.

In accordance with the present invention, the cells are subdivided intoa plurality of longitudinally extending compartments 7. The compartmentsare formed, for example, by welding the inner and outer shells of themassaging sleeve along the boundaries of the compartments. Thecompartments in a given cell are confluent due to perforations 8 in theseams between adjacent compartments so that all the compartments in thecell are inflated or deflated essentially simultaneously. Eachcompartment, when inflated, assumes essentially the shape of a cylinderhaving its axis parallel to that of the limb.

A cross-section of a deflated cell is shown in FIG. 4a, and FIG. 4bshows the same cross-section after inflation. The cell has been divided,by way of example, into ten identical compartments, it beingself-evident that any other number of compartments may be used. If N isthe number of compartments in a given cell, and r is the radius of aninflated compartment, then as can be seen in FIG. 4b the length of thecircumference 10 that passes through the centers of the inflatedcompartments will be 2Nr, whereas the circumference 9′ of the deflatedcell is Nπr. The fractional decrease in the circumference upon inflationis thus $\begin{matrix}{\frac{{N\quad \pi \quad r} - {2N\quad r}}{\pi \quad N\quad r} = {{1 - \frac{2}{\pi}} = 0.36}} & (1)\end{matrix}$

The length of the inner circumference 9″ of the inflated cell will beless than 2Nr so that the fractional decrease in the inner circumferenceupon inflation is thus greater than 0.36.

N and r are chosen so that πNr (the circumference of the deflated cell)corresponds to the original circumference of the limb segment containedwithin the lumen of the cell. The fractional decrease in thecircumference of the cell upon inflation (0.36) causes a contraction ofthe cell whereby pressure is applied to the limb which, as follows fromequation (1) above, is independent of N and r. Thus, by choosing Nsufficiently large, and r correspondingly small, a sleeve is obtainedhaving an inflated outer circumference not substantially larger than theoriginal circumference of the limb. This is in contrast to prior artdevices which, as shown above, must have a circumference 36% greaterthan the initial circumference of the limb in order to achieve the sameapplied pressure as that produced by the present invention.

Letting now L be the length of a cell and C=Nπr, the initialcircumference of the limb contained within the cell, it is readilyappreciated from FIG. 4 that the initial volume of the limb containedwithin the deflated cell is$V_{D} = {{\pi \left( \frac{C}{2\pi} \right)}^{2}{L.}}$

The final volume of the limb contained within the inflated cell is lessthan$V_{I} = {{{\pi \left( \frac{0.64C}{2\pi} \right)}^{2}L} = {0.41{V_{D}.}}}$

Inflating the cell thus leads to a decrease in the volume of the limbcontained within the cell of about 59%. This represents the volume offluid squeezed out of the limb, or the work performed by the sleeve.This is accomplished by inflating the compartments of the cell to atotal volume of V_(T)=Nπr²L=${N\quad {\pi \left( \frac{C}{N\quad \pi} \right)}^{2}L} = {\frac{C^{2}L}{N\quad \pi}.}$

In contrast to this, obtaining the same decrease in the volume of thelimb by prior art methods requires inflating a cell to a final volume of$V_{F} = {{\pi \left\{ {\left( \frac{1.36C}{2\pi} \right)^{2} - \left( \frac{0.64C}{2\pi} \right)^{2}} \right\} L} = {\frac{C^{2}L}{2.8\quad \pi}.}}$

Thus, when the number of compartments in the cell of the presentinvention is at least 3, the volume to which the cell must be inflatedis less than that of prior art devices. Moreover, by choosing Nsufficiently large, a decrease of 59% in the volume of the limb can beobtained by inflating the cell to an arbitarily small total volume. Forexample, when N=30, the total volume of the inflated cell is less thanone-tenth of the volume of the inflated cell of the prior art devices.This allows a much smaller compressor to be used than is possible withprior art sleeves, thus permitting the patient to be ambulatory whilebeing treated by the invention.

It is noted that a sleeve according to the invention, e.g. such assleeve 1 in FIGS. 1 and 2 or a smaller sleeve covering only a portion ofa limb, may be used for immobilization of a fractured bone in a limb.

What is claimed is:
 1. A device for applying pressure to a body limbhaving a primary axis comprising: first and second inflatable cells,each of the first and second cells including at least three intra-cellcompartments; said intracell compartments being confluent, eachcompartment being elongated along a longitudinal axis and beingsubstantially rectangular in shape when deflated and substantiallycylindrical in shape when inflated, the longitudinal axes of thecompartments substantially aligning with the primary axis of the limb,the first and second cells being longitudinally adjacent each other, andarranged coaxially with respect to the primary axis of the limb, thefirst and second cells being intermittently inflatable to apply pressureto the limb, wherein the inflatable cells each comprise inner and outershells of durable flexible material, said inner and outer shells beingbonded together about a perimetric cell bond to define the inflatablecell therebetween, said inner and outer shells being further bondedtogether along compartmental bonds within the perimetric cell bond todefine the plurality of intra-cell compartments, wherein the perimetriccell bond includes upper and lower perimetric cell bonds extendingsubstantially in a lateral direction, and left and right perimetric cellbonds extending substantially in the longitudinal direction, and whereinthe compartmental bonds partly extend between the upper and lowerperimetric cell bonds, wherein the compartmental bonds includeperforations to allow for confluent air flow between compartments withina cell, neighboring compartments along a lateral axis sharing a commonborder and being spatially fixed relative to each other, such that uponinflation of a cell, the cell becomes circumferentially constricted, thefirst and second cells being non-confluent such that that the first andsecond cells are separately inflatable, said intra-cell compartments ofthe first and second cells being interdigitated; means for laterallycoupling outermost compartments so as to form a sleeve, such that thesleeve has a circumference of Nπr when the cell is deflated, and suchthat the sleeve has a circumference of 2Nr when the cell is inflated,where N is the number of compartments in the cell, and where r is thecross-sectional radius of each compartment when inflated, so as toprovide for circumferential constriction; inflating means forintermittently inflating the first and second cells; and control meansfor determining the temporo-spatial regime of cell inflation.
 2. Thedevice of claim 1 wherein the fractional decrease in the circumferenceupon inflation is 0.36.
 3. The device of claim 1 wherein the bondcomprises a weldment.
 4. The device of claim 1 wherein adjacentcompartments are contiguous.
 5. The device of claim 1 wherein theperforations are located adjacent the perimetric cell bond.
 6. Thedevice of claim 1 wherein the perforations are located betweencompartmental bonds extending from the upper and lower perimetric bonds.7. The device of claim 1 further comprising a fluid inlet to provide forinflation and deflation of the cell.